Background: Studies have shown telomerase activity to be present in some B-cell non-Hodgkin lymphomas (B-NHLs). However, no large studies have assayed telomerase activity in a systematic and quantitative manner. Furthermore, the relation between telomerase and proliferation suggested by in vitro studies has not been adequately tested in B-NHLs in vivo. This information is necessary to understand the relation between proliferation and telomerase and to predict the efficacy of antitelomerase drugs currently in development.
Methods: Eighteen benign biopsies and 111 B-NHLs of varying types were classified according to the revised European-American classification of lymphoid neoplasms (REAL classification) and assayed for telomerase activity and proliferation index (PI).
Results: All B-NHLs contained telomerase activity except for low grade marginal zone B-cell lymphomas (MZBCLs) (96 of 111, 86%) (chi(2) 95.90, P < 0.001). Telomerase activity correlated with PI (r = 0.7536, r(2) = 0.5678, t = 10.51, P < 0.001) and showed a threshold whereby telomerase activity was not present below a PI of 9.2% (t = 4.875, P < 0.001).
Conclusions: The level of telomerase activity fell within characteristic ranges and generally correlated with the clinical aggressiveness of each B-NHL category. Low grade MZBCLs of extranodal, nodal, and splenic types were unique among the categories of B-NHL in lacking or containing very little telomerase activity. The association between telomerase activity and PI is evidence that telomerase is controlled in vivo along with the cell cycle and is not constitutively active in B-NHL. These data provide evidence that antitelomerase drugs may be efficacious in most types of B-NHL.
Copyright 2000 American Cancer Society.